Valve tappet



I March 28, 1939. J L DOSTAL 2,152,403

VALVE TAPPET Fi led June 18, 1938 INVENTOR Y I jasfaz Patented Mar. 28,1939 UNITED STATES PATENT OFFICE VALVE TAPPET Application June 18, 1938,Serial No. 214,492

'7' Claims.

This invention relates to valve tappets of the barrel type andparticularly to such valve tappets that are of a one-piece cast type,and has particular reference to the rough cast blank from which suchvalve tappets are formed, the principal object being the provision of ablank for such tappet that particularly lends itself to the productionof difierent forms of such tappets and to tappets formed from suchblanks having certain novel features of construction rendering themparticularly advantageous for use.

Objects of the invention include the provision of a one-piece casthollow blank for a barrel type valve tappet so constructed and arrangedthat by machining away various portions thereof valve tappets ofdifierent forms may be produced from identical blanks; the provision ofa valve tappet blank as above described provided with more than twosolid transverse walls; the provision of a one-piece cast hollow valvetappet blank having opposite end walls and an intermediate wall, theside walls of the tappet on either side of the intermediate wall beingprovided with windows therethrough; and the provision of a one-piecehollow cast iron valve tappet blank including three axially spacedtransverse walls and hollow cylindrical connecting walls, that portionof the hollow cylindrical walls connecting the intermediate wall witheach of the end walls being provided with a plurality of windowstherethrough, and the windows on one side of the intermediate wall beingangularly staggered with respect to the windows on the opposite sidethereof.

Other objects of the invention include the provision of a valve tappetcomprising a hollow cylindrical body portion each end of which isprovided with a group of angularly spaced windows extendingtherethrough, the windows in one group being staggered angularly aboutthe axis of the tappet with respect to the windows in the group at theopposite end of the tappet; the provision of a one-piece, hollow, castbarrel type valve tappet the peripherally outer walls of which areprovided at one end with three equally angularly spaced windowstherethrough and three equally angularly spaced windows at the oppositeend thereof, the windows at one end being angularly staggered withrespect to the windows at the opposite end; the provision of a valvetappet of the type just described having three axially spacedtransversely extending solid walls; the provision of a one-piece hollowcast valve tappet having opposite end walls and an intermediate wall,the side walls of the tappet on either side of the intermediate wallbeing provided with a plurality of windows therein; the provision of avalve tappet as last described in which the windows on one side of theintermediate wall are angularly staggered with respect to the windows onthe opposite side thereof; and the provision of a one-piece hollow valvetappet of cast construction provided with a plurality of Windows in theside walls thereof which windows are so arranged as to distribute thewearing surfaces of the tappet in such a manner as to result in evenwearing of the peripheral surfaces thereof in service.

The above being among the objects of the present invention the sameconsists in certain novel features of construction and combinations ofparts to be hereinafter described with reference to the accompanyingdrawing, and then claimed, having the above and other objects in View.

In the accompanying drawing which illustrates suitable embodiments ofthe present invention and in which like numerals refer to like partsthroughout the several difierent views,

Fig. 1 is a partially broken, partially sectioned side elevational viewof one form of a rough cast tappet blank constructed in accordance withthe present invention;

Fig. 2 is a view'similar to Fig. 1 but illustrating a slightly modifiedform of construction;

Figs. 3 and 4 are transverse sectional views taken on the lines 3-3 and4-4, respectively, of either Figs. 1 or 2;

Fig. 5 is a vertical sectional view taken axially through one form offinished tappet which may be formed from the blanks shown in Figs. 1 or2;

Figs. 6 and 7 are views similar to Fig. 5 but illustrating machining ofthe blank to provide different types of tappets;

Fig. 8 is a vertical sectional View taken axially through a completedtappet formed from the blank shown in Fig. 2 and machined to provide athreaded opening for reception of a conventional valve clearanceadjusting screw;

Fig. 9 is a top plan view of the tappet shown in Fig. 8.

In one-piece hollow cast iron valve tappets it is conventional practiceto provide a plurality of-windows in the side walls thereof. In the pastthese windows have been arranged either in one group around the tappetand consequently each in angularly spaced relation with respect to itsneighbor, or else have been provided in two groups with the windows ofone group axially aligned with the windows of the other group.

This arrangement in conventional tappet practice has resulted in areasof increased wear in service angularly about the axis of the tappetwhich is undesirable in practice. According to the present inventionthis detrimental feature of conventional valve tappets of the typereferred to is overcome by forming a group of windows in the tappetadjacent each end of the tappet, the windows of each group preferablybeing equally angularly spaced about the axis of the tappet, and thewindows of one group being angularly staggered with respect to thewindows of the other group, this having the effect of providing a moreeven distribution of the wearing surfaces angularly about the axis ofthe tappet than in conventional constructions.

Conventional tappets of the type referred to are provided with a maximumof two transverse walls one located at each end of the tappet.Particularly where the side walls of the tappet are unusually thin,being substantially unsupported in their central portion, they are notonly subject to warpage and other deformation in service, but they alsooffer certain difficulties in machining and grinding. The presentinvention provides a construction wherein this difficulty inconventional constructions is avoided by the provision of an additionalcross or transverse wall intermediate the length of the tappet. Not onlydoes this intermediate wall serve to strengthen the side walls of thetappet against deformation but in certain cases it may further serve asa supporting wall for a push rod or other valve operating part.Particularly where the windows for the tappet are arranged in groups onopposite sides of the intermediate wall advantages result not possiblein this type of tappet constructed in accordance with conventionalpractice.

The present invention particularly deals with a rough cast tappet blankof such construction and arrangement that by the use of identical blanksa plurality of structurally different valve tappets may be produced. Theadvantage of the present invention in this respect is that it isnecessary to cast only one type of blank and then by machining the blankdifferently different structural types of valve tappets may be producedin any desired quantity.

Referring now to Fig. 1 of the drawing which illustrates a valve tappetblank in condition received from the foundry, that is in rough castcondition, it will be noted that it includes a hollow approximatelycylindrical side wall portion I having a solid integral top end Wall I2closing such end, a solid integral bottom end wall I4 closing thecorresponding end and the axially outer portion of which is formed ofchilled cast iron as indicated at I6, and an intermediate integral solidwall I8. The wall I8 may be formed at any desired location axially ofthe tappet between the walls I2 and I4 but for the purpose ofillustration is shown as being located slightly closer to the wall I4than to the wall I2. As indicated in Fig. 1 the peripheral surface ofthe tappet blank is illustrated as being formed to correspond to theouter surfaces of two truncated cones arranged in axial alignment andwith their small ends in abutting relationship, this conformationresulting from the preferred method of casting this type of tappet andas necessitated by the draft required to withdraw the pattern for thesame from the mold. This feature, however, has no importance as far asthe present invention is concerned and the peripheral surfaces of theblank may be considered truly cylindrical as far as the presentdescription is concerned. The side wall portion I0 above theintermediate wall I8 is provided with a plurality of windows 28therethrough and the side wall portion between the walls I4 and I8 isprovided with a plurality of windows 22 therethrough. In the broaderaspects of the present invention the Windows 26 and 22 may be providedin groups of any desired number, but in a more limited aspect of thepresent invention there are preferably three Windows 20 and threewindows 22, the windows 20 being angularly staggered about the axis ofthe tappet with respect to the windows 22. It may be noted that themetal of the side walls It about the margins of both the openings 20 and22 is inwardly rounded or beveled as at 24, this being desirable in thefinished product in order to eliminate any sharp cutting edges at themargins of the various windows which might serve to scrape oil off ofthe bore in the internal combustion engine provided for reception ofsuch tappet.

The tappet blank illustrated in Fig. 2 is identical to the tappet blankillustrated in Fig. 1 except in one particular, and, accordingly,corresponding parts are indicated by corresponding numerals. The onlydifference between the tappet blank illustrated in Fig. 2 and thatillustrated in Fig. l is that in Fig. 2 the upper wall I2 is providedwith an axially outwardly projecting boss 26 formed integrally therewithand the purpose of which will be described in detail in connection withthe description of Figs. 8 and 9.

It may be noted that the relation of the diameter of the tappet andtappet blanks shown in the accompanying drawing compared to the lengththereof is conventional and will usually be of a ratio not exceeding oneto three. It may also be noted that particularly where there are threewindows 20 and three windows 22 and the windows 20 are angularlystaggered with respect to the windows 22, the only successful method ofcasting-these tappet blanks commercially in large quantities, as faras-I am aware, is that disclosed inmy co-pending'application for LettersPatent of the United States filed on even date herewith for improvementsin Method of making valve tappets and the like, and serially numbered214,491.

Referring now to Fig. one type of completely machined and finished valvetappet is shown and which may be constructed from either of the blanksillustrated in Figs. 1 and 2. Ordinarily it will be constructed from ablank such as shown in Fig. l for the reason that no axially extendingboss such as the boss 28 is necessary at one end thereof. The valvetappet shown in Fig. 5 is identical to the blank shown in Fig. 1 exceptthat the peripheral surfaces thereof have been machined to perfectlycylindrical conformation from end to end and the opposite end facesthereof have been machined flat. Technically speaking the exposedsurface of the chilled portion iii of the bottom end wall I4 is too hardto be machinable in the ordinary sense of the word and because of itshardened character a grinding operation must be relied upon to bring itto the smooth fiat condition demanded in the final product. For thepurpose of ease and simplicity in description, in view of the fact thatthe finished valve tappets illustrated in Figs. 5 to 9, inclusive, areidentical to corresponding portions of the rough blanks illustrated inFigs. 1 and 2, corresponding parts are indicated by correspondingnumerals in these later. views and, accordingly, as far asthetappetshown'in Fig. 5 is concerned, no further description of'the sameis necessary.

The valve tappet illustratedin Fig. 6 is identical to the valve tappetillustrated in Fig. 5 except that the upper wall I2 is machined toprovide a central opening 28 therein, to accommodate the passage of avalve push rod downwardly therethrough, and the upper surface of theintermediate wall I8 is provided with a partially spherical pocket orrecess 30 therein for reception of the lower end of such push rod, thistype of construction being favored under some circumstances. Obviouslythe valve tappet shown in Fig. 6 may be constructed from a blank asshown in either Figs. 1 or 2 although ordinarily the blank shown in Fig.1 will be employed as in such case it necessitates only machining thewall I2 to provide the opening 28, whereas if the blank shown in Fig. 2were employed it would be necessary to also remove the boss 26.

The valve tappet illustrated in Fig. '7 is identical to the valvetappets illustrated in Figs. 5 and 6 except that in this case not onlyis the upper wall I2 machined to provide a central opening 28 thereinbut the intermediate wall I8 is machined to provide a similar opening 32therein, the opening 32 being provided for the same purpose as theopening 28, namely to permit the passage of a valve push rod downwardlytherethrough and in such case the upper surface of the bottom wall I4will preferably be formed to provide a partially spherical or otherwiseshaped recess or pocket 34 therein for the reception of the lower end ofa push rod as is desirable in some cases. It may be noted that in theconstruction illustrated in Figs. 6 and '7 the diameters of the openings28 and 32 may be such that while a push rod may be loosely receivedtherein they will serve as a guide in directing the lower end of thepush rod into the corresponding pocket 30 or 34 provided in such case.

The tappet illustrated in Figs. 8 and 9 is identical to the blankillustrated in Fig. 2 except that the peripheral surfaces thereof havebeen machined to provide a true cylinder, the outer face of the bottomwall I4 has been machined in the same manner as the tappets previouslydescribed and the corresponding outer face of the end Wall I2 has beenmachined to form the boss 26 into a true cylinder, preferably to providea pair of flats 36 at diametrically opposite sides thereof for receptionof a wrench, and to provide an axially threaded opening 38 in the boss26 and through the end wall I2 for reception of a suitable orconventional valve clearance adjusting screw (not shown).

From the above -it will be understood that all of the tappetsillustrated in Figs. 5, 6, '7 and 8 could be produced from identicalblanks of the type shown in Fig. 2 and that all of the tappets shown inFigs. 5, 6 and 7 could be produced from identical blanks of the typeshown in Fig. l. The tappets shown in Figs. 5 and 8 being provided withthree axially spaced solid transverse walls, the side wall portions ofthe tappet are reinforced to a maximum extent against distortion andwarpage or the like, and even where the wall l2 or both the walls I2 andI8 are machined to provide a central opening therein as illustrated inFigs. 6 and '7, respectively, that portion of the walls I2 and I8remaining provide inwardly projecting rib portions which impart amaterial added rigidity to the tappet. It will also be observed that inall of the tappet constructions .is provided with a substantiallyuniform wearing surface circumferentially of .the same. Accordingly, theconstruction.- provided embodies a number of novel and advantageousfeatures not found in heretofore suggested constructions.

Formal changes may be made in the specific embodiments of the inventiondescribed without departing from the spirit or substance of the broadinvention, the scope of which is commensurate with the appended claims.

What I claim is:

1. A blank for a valve tappet comprising, in combination, a hollowgenerally cylindrical body portion, and three axially spaced imperforatetransverse walls integrally joined thereto.

2. A one-piece blank for a valve tappet comprising, in combination, ahollow generally cylindrical body portion, an end wall closing one endof said body portion, an end wall closing the opposite end of said bodyportion, and a transverse wall integrally joined to said body portioninteriorly thereof and in axially spaced relation with respect to saidend walls, all of said walls being imperforate.

3. A blank for a valve tappet comprising, in combination, a tubular bodyportion, an end wall adjacent one end of said body portion integrallyunited thereto, an end wall adjacent the opposite end of said bodyportion integrally united thereto, and a solid transverse wall Withinsaid body portion intermediate the first two mentioned walls.

4. A valve tappet comprising a generally cylindrical hollow body portionand an imperforate end wall integral therewith at each end thereof, saidbody portion adjacent one end thereof having three openings therethrougharranged in approximately equally angularly spaced relation with respectto each other and with their longitudinal center lines substantiallyparallel to the axis of said body portion, said body portion havingthree like openings therethrough adjacent the opposite end thereof andarranged in approximately equally angularly spaced relation with respectto each other, said openings adjacent one end of said main body portionbeing angularly staggered with respect to the said openings at theopposite end thereof.

5. A valve tappet comprising a generally cylindrical hollow bodyportion, a wall integrally united thereto and closing one end of saidbody portion, the axially outer face of said wall being of a relativelyhard nature, a second wall positioned interiorly of said main bodyportion intermediate the ends thereof and integrally united thereto.said second wall having a pocket formed centrally thereof in the facethereof opposite the first mentioned wall, and a radially inwardlyprojecting rib on the interior surface of said main body portion inaxially spaced relation with respect to said second wall and on thatside thereof opposite the first mentioned wall.

6. A valve tappet comprising a generally cylindrical hollow bodyportion, a transverse wall integrally united thereto adjacent each endthereof, a third transverse wall positioned interiorly of and integrallyunited to said main body portion intermediate the first two mentionedwalls, said main body portion having a group of openings therethroughbetween said third wall and each of the first two mentioned walls, theopenings of each of said groups being arranged in angularly spacedrelation, and the axially outer portion of one of the two firstmentioned walls being of a, relatively hard and 1m:- machinable nature.

7. A rough east 'unmachined hollow integral barrel type valvetappetrblan'k comprising, in

combination, aipair'of axially spaced imperforate transverse walls, a,hollow cylindrical main body portion connecting said wallsend having a,window therethroughysaid main body portion around the nun-gins of 'said:window :bei-ng inwardly relieved whereby to eliminate the occurrence ofa. sharp edge'at saiid margin a-fter. machining said 5 blank.

JOSEPH L; DOSTAL.

